#include <stdio.h>

double fat(double x, double y, int n)
{
    switch (n)
    {
    case'+':
        return x + y;
    case'-':
        return x - y;
    case'*':
        return x * y;
    case'/':
        return x / y;
    }
}

double fbt1(double a, double b, double c, double d, char* x, char* y, char* z)
{
    double ret = 0;
    ret = fat(a, b, x);
    ret = fat(ret, c, y);
    ret = fat(ret, d, z);
    return ret;
}

double fbt2(double a, double b, double c, double d, char* x, char* y, char* z)
{
    double ret = 0;
    ret = fat(b, c, x);
    ret = fat(a, ret, y);
    ret = fat(ret, d, z);
    return ret;
}

double fbt3(double a, double b, double c, double d, char* x, char* y, char* z)
{
    double ret1 = 0;
    double ret2 = 0;
    double ret = 0;
    ret1 = fat(a, b, x);
    ret2 = fat(c, d, y);
    ret = fat(ret1, ret2, z);
    return ret;
}

double fbt4(double a, double b, double c, double d, char* x, char* y, char* z)
{
    double ret = 0;
    ret = fat(c, d, x);
    ret = fat(b, ret, y);
    ret = fat(a, ret, z);
    return ret;
}

int main()
{
    int ret = 0;
    int sign = 0;
    char arr[] = { '+','-','*','/' };
    double a, b, c, d;
    scanf("%lf%lf%lf%lf", &a, &b, &c, &d);
    for (int i = 0; i < 4; i++)
    {
        for (int j = 0; j < 4; j++)
        {
            for (int k = 0; k < 4; k++)
            {
                ret = fbt1(a, b, c, d, arr[i], arr[i], arr[i]);
                ret /= 24;
                if (ret <= 0.00001 && ret >= -0.00001)
                {
                    sign = 1;
                }

                ret = fbt2(a, b, c, d, arr[i], arr[i], arr[i]);
                ret /= 24;
                if (ret <= 0.00001 && ret >= -0.00001)
                {
                    sign = 1;
                }

                ret = fbt3(a, b, c, d, arr[i], arr[i], arr[i]);
                ret /= 24;
                if (ret <= 0.00001 && ret >= -0.00001)
                {
                    sign = 1;
                }

                ret = fbt4(a, b, c, d, arr[i], arr[i], arr[i]);
                ret /= 24;
                if (ret <= 0.00001 && ret >= -0.00001)
                {
                    sign = 1;
                }
            }
        }
    }

    if (sign == 1)
    {
        printf("yes\n");
    }
    else
    {
        printf("no\n");
    }

    return 0;
}